"Sustainable procurement is no longer a nice-to-have – it's an integral business function responsible for protecting and improving brand reputation, driving revenue and mitigating business risk," said Pierre-François Thaler, EcoVadis co-CEO.

According to the survey, nearly half (45 percent) of organizations said their sustainable procurement program covers 75 percent or more of their spend volume, up from 27 percent that reported the same in 2013.

However only 15 percent admitted they have complete supply chain visibility into the CSR and sustainability performance of both tier one and two suppliers, and only six percent reported full visibility into tier three suppliers and beyond.

EcoVadis said its study also found that organizations collecting sustainability data are now using it to guide sourcing decisions. "By making CSR data a key factor in the sourcing process, organizations are incentivizing suppliers to be more sustainable and act more responsibly across the board," explained Thaler.

In its last survey conducted in 2013, the rating company found the main obstacle to supply chain and procurement sustainability was a lack of executive and board support.

This year "the C-suite appears to be finally on board with sustainable procurement initiatives," Thaler declared. "However, when you dive deeper into the data, an interesting picture starts to appear. While executives are finally on board, procurement teams still report that a lack of internal resources holds them back," he added.

The EcoVadis data confirms a study published last month by Unilever that revealed 33 percent of consumers are now choosing to buy from brands they believe are doing social or environmental good.

The study asked 20,000 adults from five countries how their sustainability concerns determined their choices both in-store and at home, and then mapped their claims against real purchase decisions. Unilever concluded there is a €966 billion sales opportunity for brands "that make their sustainability credentials clear".

Pictured: Tea pickers work on a Unilever Lipton estate in Kenya. As the world's No.1 tea producer, in 2007 Unilever became the first company to commit to sustainably sourcing tea on a large scale.